U.S. patent number 11,018,118 [Application Number 16/476,568] was granted by the patent office on 2021-05-25 for backlight device and manufacturing method thereof.
This patent grant is currently assigned to Wuhan China Star Optoelectronics Technology Co., Ltd.. The grantee listed for this patent is Wuhan China Star Optoelectronics Technology Co., Ltd.. Invention is credited to Yong Yang.
United States Patent |
11,018,118 |
Yang |
May 25, 2021 |
Backlight device and manufacturing method thereof
Abstract
A backlight device and a manufacturing method thereof are
provided. The backlight device includes a substrate, a
Light-Emitting Diode (LED) layer and a band-pass filter. The LED
layer is disposed on the substrate and includes a plurality of LED
chips arranged at intervals. The band-pass filter is disposed on
the LED layer and is provided with openings formed at positions
corresponding to the LED chips.
Inventors: |
Yang; Yong (Wuhan,
CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Wuhan China Star Optoelectronics Technology Co., Ltd. |
Wuhan |
N/A |
CN |
|
|
Assignee: |
Wuhan China Star Optoelectronics
Technology Co., Ltd. (Wuhan, CN)
|
Family
ID: |
65161338 |
Appl.
No.: |
16/476,568 |
Filed: |
November 23, 2018 |
PCT
Filed: |
November 23, 2018 |
PCT No.: |
PCT/CN2018/117233 |
371(c)(1),(2),(4) Date: |
July 09, 2019 |
PCT
Pub. No.: |
WO2020/062522 |
PCT
Pub. Date: |
April 02, 2020 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20200203320 A1 |
Jun 25, 2020 |
|
Foreign Application Priority Data
|
|
|
|
|
Sep 30, 2018 [CN] |
|
|
201811155955.9 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L
33/46 (20130101); H01L 33/58 (20130101); G02F
1/133611 (20130101); H01L 33/62 (20130101); G02F
1/133606 (20130101); H01L 25/0753 (20130101); G02F
1/133603 (20130101); G02F 1/133605 (20130101); H01L
2933/0025 (20130101); H01L 2933/0091 (20130101); H01L
2933/0066 (20130101); H01L 2933/0058 (20130101) |
Current International
Class: |
H01L
25/075 (20060101); H01L 33/58 (20100101); H01L
33/62 (20100101); G02F 1/13357 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
111146231 |
|
May 2020 |
|
CN |
|
2014165062 |
|
Sep 2014 |
|
JP |
|
WO-2012121372 |
|
Sep 2012 |
|
WO |
|
Other References
US 10,854,670 B2, 12/2020, Chae (withdrawn) cited by
examiner.
|
Primary Examiner: Santiago; Mariceli
Claims
What is claimed is:
1. A backlight device, comprising: a substrate; a Light-Emitting
Diode light-emitting diode (LED) layer disposed on the substrate
and comprising a plurality of LED chips arranged at intervals; a
band-pass filter disposed on the LED layer, wherein the band-pass
filter is provided with a plurality of openings that are formed at
positions corresponding to the LED chips, and the band-pass filter
allows blue light to transmit therethrough; and at least one
diffusion layer disposed on the band-pass filter and receives light
emitted from the LED layer through the openings on the band-pass
filter.
2. The backlight device according to claim 1, wherein the LED chips
are mini LED chips each having a size of 100 .mu.m to 200 .mu.m,
and the LED chips comprise red, green and blue LED chips.
3. The backlight device according to claim 1, wherein the substrate
at least comprises a metal wire layer and an insulating layer.
4. The backlight device according to claim 1, wherein the backlight
device further comprises at least one brightness enhancement film
which is disposed on the at least one diffusion layer.
5. The backlight device according to claim 1, wherein the LED layer
is coated with a transparent filling layer, and the transparent
filling layer is filled in gaps between the LED chips arranged at
intervals and has the same height as the LED chips.
6. A backlight device, comprising: a substrate; a Light-Emitting
Diode light-emitting diode (LED) layer disposed on the substrate
and comprising a plurality of LED chips arranged at intervals; and
a band-pass filter disposed on the LED layer, wherein the band-pass
filter is provided with a plurality of openings that are formed at
positions corresponding to the LED chips.
7. The backlight device according to claim 6, wherein the backlight
device further comprises at least one diffusion layer disposed on
the band-pass filter and receives light emitted from the LED layer
through the openings on the band-pass filter so that the light is
dispersed uniformly.
8. The backlight device according to claim 7, wherein the LED chips
comprise red, green and blue LED chips.
9. The backlight device according to claim 8, wherein the substrate
at least comprises a metal wire layer and an insulating layer.
10. The backlight device according to claim 6, wherein the LED
device further comprises at least one brightness enhancement film
which is disposed on the at least one diffusion layer.
11. The backlight device according to claim 8, wherein the LED
chips are mini LED chips each having a size of 100 .mu.m to 200
.mu.m.
12. The backlight device according to claim 6, wherein the LED
layer is coated with a transparent filling layer, and the
transparent filling layer is filled in gaps between the LED chips
arranged at intervals and has the same height as the LED chips.
13. The backlight device according to claim 6, wherein the
band-pass filter is prepared on a high-temperature-resistant
transparent plastic plate.
14. A method for manufacturing a backlight device, comprising the
following steps of: providing a substrate; providing a
Light-Emitting Diode light-emitting diode (LED) layer on the
substrate, the LED layer comprising a plurality of LED chips
arranged at intervals; and providing a band-pass filter on the LED
layer, wherein a plurality of openings are formed on the band-pass
filter at positions corresponding to the LED chips.
15. The method for manufacturing a backlight device according to
claim 14, further comprising the following steps of: forming at
least one diffusion layer on the band-pass filter; and forming at
least one brightness enhancement film on the at least one diffusion
layer.
16. The method for manufacturing a backlight device according to
claim 14, wherein the LED chips comprise red, green and blue LED
chips.
17. The method for manufacturing a backlight device according to
claim 14, wherein the substrate at least comprises a metal wire
layer and an insulating layer.
18. The method for manufacturing a backlight device according to
claim 14, wherein the LED chips are mini LED chips each having a
size of 100 .mu.m to 200 .mu.m.
19. The method for manufacturing a backlight device according to
claim 14, wherein the LED layer is coated with a transparent
filling layer, and the transparent filling layer is filled in gaps
between the LED chips arranged at intervals and has the same height
as the LED chips.
20. The method for manufacturing a backlight device according to
claim 14, wherein the band-pass filter is prepared on a
high-temperature-resistant transparent plastic plate.
Description
RELATED APPLICATIONS
This application is a National Phase of PCT Patent Application No.
PCT/CN2018/117233 having International filing date of Nov. 23,
2018, which claims the benefit of priority of Chinese Patent
Application No. 201811155955.9 filed on Sep. 30, 2018. The contents
of the above applications are all incorporated by reference as if
fully set forth herein in their entirety.
FIELD AND BACKGROUND OF THE INVENTION
The present application relates to the technical field of display,
and in particular to a backlight device and a manufacturing method
thereof.
As a strong competitor for the OLED display technology in the
future market, mini Light-Emitting Diodes (LEDs) are LEDs in size
between conventional LEDs and micro LEDs. Since the mini LEDs are
high in brightness, can be fabricated on a flexible substrate, can
be applied to the high dynamic contrast display technology, the
narrow bezel display technology and the special-shaped display
technology and the like, the mini LEDs have become a hot topic in
market research. However, mini LEDs are still inferior to the
conventional backlight products and the OLED display technology in
terms of luminous efficiency, uniformity of light mixture, cost and
the like. For example, in a direct backlight architecture in which
a mini LED is fabricated on a printed circuit board or a flexible
circuit board, due to the difference in refractivity, part of light
from a surface light source is restricted between the films and the
substrate and thus cannot be emitted; moreover, multiple times of
refraction of light between films result in the loss of light
energy and the reduction in luminous efficiency. For a film, the
transmittance of light is also somewhat limited. How to improve the
luminous efficiency of LED chips and reduce the loss of light
inside the surface light source has become a primary issue in the
improvement of the luminous efficiency of the surface light
source.
Therefore, it is necessary to provide a backlight device and a
manufacturing method thereof to solve the problems in the prior
art.
SUMMARY OF THE INVENTION
In view of the defects in the prior art, a main objective of the
present invention is to provide a backlight device and a
manufacturing method thereof, which can reduce the internal light
echo loss and improve the overall luminous efficiency of a surface
light source.
For this purpose, the present invention provides a backlight
device, including: a substrate; a Light-Emitting Diode (LED) layer,
which is disposed on the substrate and comprises a plurality of LED
chips arranged at intervals; and, a band-pass filter which is
disposed on the LED layer, wherein openings are formed on the
band-pass filter at positions corresponding to the LED chips.
In one embodiment of the present disclosure, the backlight device
further comprises at least one diffusion layer disposed on the
band-pass filter and receives light emitted from the LED layer
through the openings on the band-pass filter so that the light is
dispersed uniformly.
In one embodiment of the present disclosure, the LED chips comprise
red, green and blue LED chips.
In one embodiment of the present disclosure, the substrate at least
comprises a metal wire layer and an insulating layer.
In one embodiment of the present disclosure, the backlight device
further comprises at least one brightness enhancement film which is
disposed on the at least one diffusion layer.
In one embodiment of the present disclosure, the LED chips are mini
LED chips each having a size of 100 .mu.m to 200 .mu.m.
In one embodiment of the present disclosure, the LED layer is
coated with a transparent filling layer, and the transparent
filling layer is filled in gaps between the LED chips arranged at
intervals and has the same height as the LED chips.
In one embodiment of the present disclosure, the band-pass filter
is prepared on a high-temperature-resistant transparent plastic
plate.
The present disclosure further provides a method for manufacturing
the aforementioned backlight device. The method comprises the
following steps of: providing a substrate; providing a
Light-Emitting Diode (LED) layer on the substrate, the LED layer
comprising a plurality of LED chips arranged at intervals; and
providing a band-pass filter on the LED layer, wherein openings are
formed on the band-pass filter at positions corresponding to the
LED chips.
In one embodiment of the present disclosure, the method for
manufacturing a backlight device further comprises steps of:
forming at least one diffusion layer on the band-pass filter; and
forming at least one brightness enhancement film on the at least
one diffusion layer.
In the present invention, by additionally providing a band-pass
filter above the LED layer, the internal light echo loss of the
mini LED device is reduced, and the overall luminous efficiency of
a surface light source is improved.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a sectional view of a backlight device according to an
embodiment of the present invention.
FIGS. 2A, 2B, 2C and 2D are schematic flowcharts of manufacturing
the backlight device of FIG. 1.
FIG. 3 is a schematic flowchart of manufacturing a band-pass filter
in the backlight device according to an embodiment of the present
invention.
FIG. 4 is a flowchart of a method for manufacturing a backlight
device according to an embodiment of the present invention.
DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION
To make the objectives, features and advantages of the present
invention more apparent and comprehensible, preferred embodiments
of the present invention will be listed and described in detail
hereinafter with reference to the accompanying drawings. Besides,
the directional terms as used here, such as "upper", "lower",
"front", "rear", "left", "right", "inner", "outer" and "side",
merely refer to the directions shown in the accompanying drawings.
Therefore, the directional terms are used for describing and
understanding the present invention, rather than limiting the
present invention.
The backlight device of the present invention may be mainly used as
a backlight source for a general flat display screen. Referring to
FIG. 1, FIG. 1 is a sectional view of a backlight device according
to an embodiment of the present invention. The backlight device
mainly includes a substrate 10, an LED layer 20 and a band-pass
filter 30, and may further include at least one diffusion layer 40
and at least one brightness enhancement film 50.
In an embodiment, the substrate 10 at least includes a metal wire
layer and an insulating layer. For example, the substrate 10 may
include a copper wire layer, a polyimide film layer and a
silkscreen layer, wherein the silkscreen layer is used for
secondarily reflecting blue light transmitting through the
band-pass filter to the at least one diffusion layer.
As shown in FIG. 1 and with reference to FIGS. 2B and 2C, the LED
layer 20 is disposed on the substrate 10 and includes a plurality
of LED chips (200, 201, 202) arranged at intervals. Specifically,
the LED chips (200, 201, 202) may include red, green and blue mini
LED chips each having a size of 100 .mu.m to 200 .mu.m. Since the
LED layer 20 provides red, green and blue light by the red, green
and blue mini LED chips, respectively, the LED layer 20 may not
have a fluorescent powder layer or a quantum dot film layer, and it
is not required to irradiate and excite the fluorescent powder
layer or the quantum dot film layer to convert light into light in
other colors by the blue mini LED chips. Accordingly, the loss of
photons during the excitation of the fluorescent powder layer or
the quantum dot film layer is avoided, and the overall luminous
efficiency of the surface light source is improved.
In an embodiment, the LED layer 20 is further coated with a
transparent filling layer 203, and the transparent filling layer
203 is filled in gaps between the LED chips (200, 201, 202)
arranged at intervals and has the same height as the LED chips
(200, 201, 202). In this way, the surface flatness of the LED layer
20 may be ensured, and it is advantageous for the arrangement of
the subsequent film layers.
As shown in FIG. 1, the band-pass filter 30 is disposed on the LED
layer 20. The band-pass filter 30 is preferably prepared on a
high-temperature-resistant transparent plastic plate. A plurality
of openings are formed on the band-pass filter 30 at positions
corresponding to the LED chips (200, 201, 202), and the surface of
the band-pass filter 30 allows blue light to transmit therethrough
but reflects red light and green light.
As shown in FIG. 1, the at least one diffusion layer 40 is disposed
on the band-pass filter 30, and receives light emitted from the LED
layer 20 through the openings on the band-pass filter 30 so that
the light is dispersed uniformly. Since the light is dispersed
uniformly, the at least one diffusion layer 40 will reflect part of
the received light to the band-pass filter 30. At this time, the
surface of the band-pass filter 30 allows blue light in the light
reflected by the at least diffusion layer 40 to transmit
therethrough, and reflects red light and green light in the
reflected light to the at least one diffusion layer 40.
As shown in FIG. 1, the at least one brightness enhancement film 50
is disposed on the at least one diffusion layer 40. In this
embodiment, the backlight device includes upper and lower
brightness enhancement films (50, 51) to gather light in a certain
angle range so as to increase the brightness on the front side of
the surface light source.
Since the light emitted from the red, green and blue LED chips
directly enters the lower surface of the diffusion layer 40 without
passing through the band-pass filter 30, part of the right in the
three colors (i.e., red, green and blue light) is reflected by the
lower surface of the diffusion later 40; the reflected blue light
is secondarily reflected by the band-pass filter 30 and the
silkscreen layer on the substrate 10 and then enters the diffusion
layer 40 again; and, the green light and the red light are almost
completely reflected to the diffusion layer 40 by the surface of
the band-pass filter 30 and will not transmit through the band-pass
filter 30 to enter the silkscreen layer on the substrate 10. By
such an optical path design, more light may be allowed to enter the
diffusion layer 40 and the light enhancement film layer 50, so that
the overall luminous efficiency of the surface light source is
improved. Meanwhile, by LED chips in three primary colors, the loss
of excitation light efficiency caused by the excitation of the
fluorescent powder layer or the quantum dot film layer by the blue
LED chips may be avoided, and more efficient luminescence may be
realized.
Further referring to FIGS. 2A-2D and FIG. 4, FIGS. 2A-2D are
schematic flowcharts of manufacturing the backlight device of FIG.
1, and FIG. 4 is a flowchart of a method for manufacturing a
backlight device according to an embodiment of the present
invention. The method for manufacturing a backlight device mainly
includes the following steps S100 to S102.
Step S100: A substrate 10 is provided, as shown in FIG. 2A, wherein
the substrate 10 may be manufactured from at least one metal wire
layer and an insulating layer, and the metal wire layer and the
insulating layer may include, for example, a copper wire layer, a
polyimide film layer and a silkscreen layer.
Step S101: An LED layer 20 is provided on the substrate 10, as
shown in FIG. 2B, wherein the LED layer 20 includes a plurality of
LED chips (200, 201, 202) arranged at intervals. Specifically, the
LED chips (200, 201, 202) may include red, green and blue mini LED
chips each having a size of 100 .mu.m to 200 .mu.m. This step may
further include a step of forming a transparent filling layer 203
by a coating process. The transparent filling layer 203 is filled
in gaps between the LED chips (200, 201, 202) arranged at
intervals, as shown in FIG. 2C.
Step S102: A band-pass filter 30 having a surface that allows blue
light to transmit therethrough and reflects red light and green
light is provided on the LED layer 20, as shown in FIG. 2D. With
reference to FIG. 3, in this step, the band-pass filter 30 is first
prepared on a high-temperature-resistant transparent plastic plate,
openings 300 are then formed at positions corresponding to the LED
chips (200, 201, 202), and the band-pass filter 30 is arranged on
the LED layer 20 by hot pressing.
The method for manufacturing a backlight device may further include
the following steps S103 to S104.
Step S103: At least one diffusion layer 40 is formed on the
band-pass filter 30, wherein the diffusion layer 40 is a resin
layer or an adhesive containing scattering particles and is used
for receiving light emitted from the LED layer 20 through the
openings on the band-pass filter 30 so that the light is dispersed
uniformly.
Step S104: At least one brightness enhancement film 50 is formed on
the at least one diffusion layer 40.
In conclusion, compared with the prior art, in the present
invention, by additionally providing, above the LED layer, a
band-pass filter for allowing blue light to transmit therethrough
and reflecting red light and green light, the internal light echo
loss of the mini LED device is reduced, and the overall luminous
efficiency of the surface light source is improved. Meanwhile, in
the present invention, by manufacturing the mini LED device by red,
green and blue LED chips, the excitation loss of photons caused by
the excitation of fluorescent powder or a quantum dot film to emit
light in other colors by blue LED chips is avoided, and the
luminous efficiency of the mini LED device is improved.
The present invention has been described above by the related
embodiments, but these embodiments are merely examples for
implementing the present invention. It is to be noted that the
disclosed embodiments are not intended to limit the scope of the
present invention. Rather, the modifications and equivalent
arrangements without departing from the spirit and scope of the
appended claims shall fall into the scope of the present
invention.
* * * * *